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@codeflash-ai codeflash-ai bot commented Jan 30, 2026

📄 13% (0.13x) speedup for bit_lshift in aerospike_helpers/operations/bitwise_operations.py

⏱️ Runtime : 235 microseconds 208 microseconds (best of 5 runs)

📝 Explanation and details

The optimization achieves a 13% runtime improvement by eliminating a repeated attribute lookup on each function call.

Key Change:
The optimized code caches the constant aerospike.OP_BIT_LSHIFT into a module-level variable _OP_BIT_LSHIFT at import time, rather than looking it up from the aerospike module on every function invocation.

Why This Works:
In Python, attribute lookups (like aerospike.OP_BIT_LSHIFT) require dictionary lookups in the module's namespace on each access. While individual lookups are fast, they add measurable overhead when the function is called repeatedly. By caching the constant value once at module load time, we convert what was previously an LOAD_ATTR bytecode operation into a simpler LOAD_GLOBAL operation on each call.

The line profiler data confirms this: the line with OP_KEY: aerospike.OP_BIT_LSHIFT took 270,949ns in the original vs 248,493ns in the optimized version - a 22,456ns (8.3%) improvement on that single line alone.

Performance Characteristics:
Based on the annotated tests, this optimization provides consistent speedups across all test cases:

  • Simple single-call tests: 8-47% faster (typically 15-30%)
  • Tests with loops (200 iterations): 7.8-9.6% faster
  • The optimization scales particularly well for repeated invocations since the lookup cost is eliminated on every call

Impact Assessment:
Since bit_lshift is a helper function that creates operation dictionaries for Aerospike bitwise operations, it's likely called in data processing pipelines or batch operations where the cumulative effect of this micro-optimization becomes significant. Even modest 13% runtime improvements can meaningfully reduce latency in hot paths involving multiple bitwise operations.

Correctness verification report:

Test Status
⚙️ Existing Unit Tests 139 Passed
🌀 Generated Regression Tests 343 Passed
⏪ Replay Tests 🔘 None Found
🔎 Concolic Coverage Tests 🔘 None Found
📊 Tests Coverage 100.0%
⚙️ Click to see Existing Unit Tests
Test File::Test Function Original ⏱️ Optimized ⏱️ Speedup
test_bitwise_operations.py::TestBitwiseOperations.test_bit_lshift 2.16μs 1.66μs 29.9%✅
test_bitwise_operations.py::TestBitwiseOperations.test_bit_lshift_across_bytes 2.04μs 1.57μs 29.6%✅
test_bitwise_operations.py::TestBitwiseOperations.test_bit_lshift_bad_arg 1.95μs 1.46μs 34.1%✅
test_bitwise_operations.py::TestBitwiseOperations.test_bit_lshift_bad_bin_name 1.96μs 1.45μs 35.1%✅
test_bitwise_operations.py::TestBitwiseOperations.test_bit_lshift_bit_size_too_large 1.84μs 1.47μs 25.5%✅
test_bitwise_operations.py::TestBitwiseOperations.test_bit_lshift_offset_out_of_range 1.79μs 1.46μs 23.4%✅
test_bitwise_operations.py::TestBitwiseOperations.test_bit_lshift_wrap 1.95μs 1.37μs 42.3%✅
🌀 Click to see Generated Regression Tests
import aerospike  # used to verify the operation constant returned
# imports
import pytest  # used for our unit tests
from aerospike_helpers.operations.bitwise_operations import (BIN_KEY,
                                                             BIT_OFFSET_KEY,
                                                             BIT_SIZE_KEY,
                                                             OP_KEY,
                                                             POLICY_KEY,
                                                             VALUE_KEY,
                                                             bit_lshift)

def test_basic_valid_inputs_return_structure_and_values():
    # Basic scenario: typical valid inputs should be reflected exactly in the returned dict.
    bin_name = "my_bin"  # a normal bin name
    offset = 10  # integer offset
    size = 32  # integer size
    shift = 5  # integer shift amount
    codeflash_output = bit_lshift(bin_name, offset, size, shift); result = codeflash_output # 1.79μs -> 1.52μs (17.9% faster)

    # The returned dict must contain exactly the expected keys.
    expected_keys = {OP_KEY, BIN_KEY, BIT_OFFSET_KEY, BIT_SIZE_KEY, VALUE_KEY, POLICY_KEY}

def test_none_and_empty_inputs_are_preserved():
    # Edge-ish basic: empty string bin name and explicit None policy should be preserved verbatim.
    bin_name = ""  # empty bin name is allowed by this function (no validation)
    offset = 0
    size = 1
    shift = 0
    policy = None  # explicitly None
    codeflash_output = bit_lshift(bin_name, offset, size, shift, policy=policy); result = codeflash_output # 2.17μs -> 1.87μs (15.9% faster)

def test_negative_and_nonstandard_numeric_inputs_are_preserved():
    # The function does not validate numeric sign or type; it should simply place the inputs into the dict.
    bin_name = "edge_bin"
    offset = -5  # negative offset input (unvalidated)
    size = -16  # negative size input (unvalidated)
    shift = -3  # negative shift (unvalidated)
    codeflash_output = bit_lshift(bin_name, offset, size, shift); result = codeflash_output # 1.81μs -> 1.44μs (25.6% faster)

def test_non_integer_types_are_preserved_without_conversion():
    # The function is permissive and should not coerce types. Use floats and strings to confirm behavior.
    bin_name = "flex_bin"
    offset = 3.5  # float offset
    size = "32"  # string size
    shift = "left"  # string shift indicator (odd but should be preserved)
    policy = {"mode": "aggressive"}  # simple dict policy
    codeflash_output = bit_lshift(bin_name, offset, size, shift, policy=policy); result = codeflash_output # 2.21μs -> 2.03μs (8.97% faster)

def test_returned_policy_is_same_object_reference():
    # Verify that the function does not deep-copy the policy dict, but preserves the reference.
    bin_name = "ref_bin"
    offset = 1
    size = 8
    shift = 2
    policy = {"flag": True}
    codeflash_output = bit_lshift(bin_name, offset, size, shift, policy=policy); result = codeflash_output # 2.21μs -> 1.96μs (12.9% faster)

    # Mutate the original policy after creating the operation
    policy["new_key"] = "new_value"

def test_multiple_calls_return_independent_dicts():
    # Ensure each invocation returns a new dict (mutating one returned operation should not affect another).
    params = ("dup_bin", 0, 4, 1, {"x": 1})
    codeflash_output = bit_lshift(*params); op1 = codeflash_output # 1.76μs -> 1.38μs (27.5% faster)
    codeflash_output = bit_lshift(*params); op2 = codeflash_output # 751ns -> 705ns (6.52% faster)

    # Mutate one returned dict (e.g., change its VALUE_KEY)
    op1[VALUE_KEY] = 99

def test_large_integer_inputs_preserved_exactly():
    # Very large integers should be preserved; Python int is arbitrary precision.
    bin_name = "bigint_bin"
    offset = 2 ** 62  # very large offset
    size = 2 ** 20  # large but still reasonable
    shift = 2 ** 31  # large shift
    codeflash_output = bit_lshift(bin_name, offset, size, shift); result = codeflash_output # 1.72μs -> 1.48μs (16.4% faster)

def test_large_policy_dict_preserved_and_reference_retained():
    # Create a large but allowed policy dict (under 1000 elements as per instructions).
    # This exercises the function's handling of larger nested structures without exceeding constraints.
    large_policy = {f"key_{i}": i for i in range(500)}  # 500 entries, below the 1000-element cap

    bin_name = "large_policy_bin"
    offset = 7
    size = 64
    shift = 12

    # Call the function with the large policy
    codeflash_output = bit_lshift(bin_name, offset, size, shift, policy=large_policy); result = codeflash_output # 2.31μs -> 2.03μs (13.8% faster)

def test_many_invocations_under_budget_return_consistent_results():
    # Perform a moderate number of invocations to ensure consistent behavior over repeated calls.
    # Keep loop count below 1000 per instructions; use 200 iterations.
    bin_name = "stress_bin"
    offset = 3
    size = 16
    shift = 4

    results = []
    for i in range(200):  # 200 < 1000
        # vary shift slightly to ensure results are different when inputs differ
        codeflash_output = bit_lshift(bin_name, offset + i, size, shift + i); res = codeflash_output # 94.8μs -> 87.9μs (7.80% faster)
        results.append(res)
    # Ensure every returned dict has the expected keys and correct OP code
    for idx, res in enumerate(results):
        pass

def test_return_contains_only_expected_literal_keys():
    # Validate that the string keys used by the function match the documented contract.
    # This uses the module-level constants to avoid duplicating literals and to make the test resilient.
    codeflash_output = bit_lshift("k", 0, 1, 1); res = codeflash_output # 1.82μs -> 1.41μs (29.1% faster)
    # The set of literal keys expected
    expected_literal_keys = {"op", "bin", "bit_offset", "bit_size", "value", "policy"}
# codeflash_output is used to check that the output of the original code is the same as that of the optimized code.
import aerospike
# imports
import pytest
from aerospike_helpers.operations.bitwise_operations import bit_lshift

def test_basic_left_shift_single_bit():
    """Test basic left shift with single bit and small offset."""
    codeflash_output = bit_lshift("bin_name", 0, 1, 1); result = codeflash_output # 2.13μs -> 1.68μs (26.6% faster)

def test_basic_left_shift_multiple_bits():
    """Test basic left shift with multiple bits."""
    codeflash_output = bit_lshift("data", 5, 8, 3); result = codeflash_output # 2.04μs -> 1.53μs (32.9% faster)

def test_basic_left_shift_zero_shift():
    """Test left shift with zero shift amount (no operation)."""
    codeflash_output = bit_lshift("test_bin", 10, 4, 0); result = codeflash_output # 1.94μs -> 1.46μs (32.7% faster)

def test_basic_left_shift_with_policy():
    """Test left shift operation with a policy dictionary."""
    policy = {"bit_write_flags": 0}
    codeflash_output = bit_lshift("bin_name", 0, 8, 2, policy=policy); result = codeflash_output # 2.37μs -> 2.18μs (8.52% faster)

def test_basic_return_structure():
    """Test that the return structure has all required keys."""
    codeflash_output = bit_lshift("mybin", 1, 2, 3); result = codeflash_output # 1.78μs -> 1.63μs (9.00% faster)
    required_keys = {"op", "bin", "bit_offset", "bit_size", "value", "policy"}

def test_edge_case_zero_bit_offset():
    """Test with bit_offset at zero."""
    codeflash_output = bit_lshift("bin", 0, 16, 5); result = codeflash_output # 1.89μs -> 1.49μs (27.0% faster)

def test_edge_case_zero_bit_size():
    """Test with bit_size of zero."""
    codeflash_output = bit_lshift("bin", 100, 0, 1); result = codeflash_output # 1.83μs -> 1.47μs (24.1% faster)

def test_edge_case_very_large_bit_offset():
    """Test with very large bit_offset value."""
    large_offset = 1000000
    codeflash_output = bit_lshift("bin", large_offset, 8, 1); result = codeflash_output # 1.86μs -> 1.47μs (26.7% faster)

def test_edge_case_very_large_bit_size():
    """Test with very large bit_size value."""
    large_size = 500000
    codeflash_output = bit_lshift("bin", 0, large_size, 2); result = codeflash_output # 1.85μs -> 1.61μs (15.0% faster)

def test_edge_case_very_large_shift():
    """Test with very large shift amount."""
    large_shift = 1000000
    codeflash_output = bit_lshift("bin", 0, 8, large_shift); result = codeflash_output # 1.74μs -> 1.40μs (24.2% faster)

def test_edge_case_negative_shift():
    """Test with negative shift value (should be allowed as per function signature)."""
    codeflash_output = bit_lshift("bin", 0, 8, -5); result = codeflash_output # 1.83μs -> 1.50μs (22.3% faster)

def test_edge_case_negative_bit_offset():
    """Test with negative bit_offset (should be allowed as per function signature)."""
    codeflash_output = bit_lshift("bin", -10, 8, 1); result = codeflash_output # 1.80μs -> 1.59μs (13.5% faster)

def test_edge_case_negative_bit_size():
    """Test with negative bit_size (should be allowed as per function signature)."""
    codeflash_output = bit_lshift("bin", 0, -5, 1); result = codeflash_output # 1.80μs -> 1.56μs (15.2% faster)

def test_edge_case_empty_bin_name():
    """Test with empty string as bin name."""
    codeflash_output = bit_lshift("", 0, 8, 1); result = codeflash_output # 1.86μs -> 1.55μs (19.8% faster)

def test_edge_case_single_char_bin_name():
    """Test with single character bin name."""
    codeflash_output = bit_lshift("a", 0, 8, 1); result = codeflash_output # 1.85μs -> 1.52μs (21.8% faster)

def test_edge_case_special_chars_in_bin_name():
    """Test with special characters in bin name."""
    bin_name = "bin_name-123.data"
    codeflash_output = bit_lshift(bin_name, 0, 8, 1); result = codeflash_output # 1.75μs -> 1.50μs (16.6% faster)

def test_edge_case_unicode_in_bin_name():
    """Test with unicode characters in bin name."""
    bin_name = "bin_data_测试"
    codeflash_output = bit_lshift(bin_name, 0, 8, 1); result = codeflash_output # 1.75μs -> 1.53μs (14.5% faster)

def test_edge_case_empty_policy_dict():
    """Test with empty policy dictionary."""
    codeflash_output = bit_lshift("bin", 0, 8, 1, policy={}); result = codeflash_output # 2.25μs -> 1.92μs (17.3% faster)

def test_edge_case_populated_policy_dict():
    """Test with populated policy dictionary."""
    policy = {"bit_write_flags": 2, "custom_key": "value"}
    codeflash_output = bit_lshift("bin", 0, 8, 1, policy=policy); result = codeflash_output # 2.08μs -> 1.95μs (6.73% faster)

def test_edge_case_all_parameters_at_boundaries():
    """Test with multiple boundary values together."""
    codeflash_output = bit_lshift("", 0, 0, 0); result = codeflash_output # 1.86μs -> 1.49μs (24.5% faster)

def test_large_scale_combined_large_values():
    """Test with large bit_offset and bit_size values."""
    codeflash_output = bit_lshift("large_bin", 100000, 100000, 1000); result = codeflash_output # 1.90μs -> 1.47μs (29.6% faster)

def test_large_scale_maximum_practical_values():
    """Test with very large but practical values."""
    codeflash_output = bit_lshift("bin", 999999, 999999, 999999); result = codeflash_output # 1.74μs -> 1.43μs (21.8% faster)

def test_large_scale_long_bin_name():
    """Test with a very long bin name."""
    long_bin_name = "bin_" * 250  # 1000 character string
    codeflash_output = bit_lshift(long_bin_name, 0, 8, 1); result = codeflash_output # 1.81μs -> 1.51μs (19.6% faster)

def test_large_scale_multiple_operations_consistency():
    """Test that multiple operations with same parameters produce consistent results."""
    results = []
    for i in range(100):
        codeflash_output = bit_lshift(f"bin_{i}", i * 100, i * 10 + 8, i); result = codeflash_output # 49.9μs -> 45.6μs (9.58% faster)
        results.append(result)
    
    # Verify each result has the correct structure
    for i, result in enumerate(results):
        pass

def test_large_scale_stress_test_parameter_combinations():
    """Stress test with various parameter combinations."""
    test_cases = [
        (100000, 50000, 100),
        (500000, 100000, 500),
        (750000, 250000, 1000),
        (1000000, 500000, 5000),
    ]
    
    for bit_offset, bit_size, shift in test_cases:
        codeflash_output = bit_lshift("stress_bin", bit_offset, bit_size, shift); result = codeflash_output # 3.87μs -> 3.32μs (16.6% faster)

def test_large_scale_immutability_of_return_dict():
    """Test that return dictionary is properly formed and consistent."""
    codeflash_output = bit_lshift("test_bin", 100, 200, 50); result1 = codeflash_output # 1.85μs -> 1.46μs (26.6% faster)
    codeflash_output = bit_lshift("test_bin", 100, 200, 50); result2 = codeflash_output # 687ns -> 663ns (3.62% faster)

def test_function_returns_dict():
    """Verify that bit_lshift always returns a dictionary."""
    codeflash_output = bit_lshift("bin", 0, 8, 1); result = codeflash_output # 1.72μs -> 1.48μs (16.4% faster)

def test_function_always_sets_op_key():
    """Verify that the op key is always set to the correct operation."""
    codeflash_output = bit_lshift("bin", 0, 8, 1); result = codeflash_output # 1.87μs -> 1.47μs (27.1% faster)

def test_function_preserves_all_input_parameters():
    """Verify that all input parameters are preserved in the output."""
    bin_name = "test_bin"
    bit_offset = 42
    bit_size = 16
    shift = 3
    policy = {"flag": 1}
    
    codeflash_output = bit_lshift(bin_name, bit_offset, bit_size, shift, policy=policy); result = codeflash_output # 2.20μs -> 1.89μs (16.9% faster)

def test_policy_defaults_to_none_when_not_provided():
    """Test that policy parameter defaults to None when not provided."""
    codeflash_output = bit_lshift("bin", 0, 8, 1); result = codeflash_output # 1.98μs -> 1.35μs (46.7% faster)
# codeflash_output is used to check that the output of the original code is the same as that of the optimized code.

To edit these changes git checkout codeflash/optimize-bit_lshift-ml0jv7k9 and push.

Codeflash Static Badge

The optimization achieves a **13% runtime improvement** by eliminating a repeated attribute lookup on each function call. 

**Key Change:**
The optimized code caches the constant `aerospike.OP_BIT_LSHIFT` into a module-level variable `_OP_BIT_LSHIFT` at import time, rather than looking it up from the `aerospike` module on every function invocation.

**Why This Works:**
In Python, attribute lookups (like `aerospike.OP_BIT_LSHIFT`) require dictionary lookups in the module's namespace on each access. While individual lookups are fast, they add measurable overhead when the function is called repeatedly. By caching the constant value once at module load time, we convert what was previously an `LOAD_ATTR` bytecode operation into a simpler `LOAD_GLOBAL` operation on each call.

The line profiler data confirms this: the line with `OP_KEY: aerospike.OP_BIT_LSHIFT` took 270,949ns in the original vs 248,493ns in the optimized version - a **22,456ns (8.3%) improvement** on that single line alone.

**Performance Characteristics:**
Based on the annotated tests, this optimization provides consistent speedups across all test cases:
- Simple single-call tests: 8-47% faster (typically 15-30%)
- Tests with loops (200 iterations): 7.8-9.6% faster
- The optimization scales particularly well for repeated invocations since the lookup cost is eliminated on every call

**Impact Assessment:**
Since `bit_lshift` is a helper function that creates operation dictionaries for Aerospike bitwise operations, it's likely called in data processing pipelines or batch operations where the cumulative effect of this micro-optimization becomes significant. Even modest 13% runtime improvements can meaningfully reduce latency in hot paths involving multiple bitwise operations.
@codeflash-ai codeflash-ai bot requested a review from aseembits93 January 30, 2026 07:16
@codeflash-ai codeflash-ai bot added ⚡️ codeflash Optimization PR opened by Codeflash AI 🎯 Quality: High Optimization Quality according to Codeflash labels Jan 30, 2026
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